LED module for flashing lamp and flashing lamp

ABSTRACT

The present invention provides an LED module that can prevent breakage of an LED chip due to pulse lighting for a flash when the LED module is used in a flashing lamp. An LED module ( 10 ) for flashing lamp includes: an LED substrate ( 13 ); plural LEDs ( 12 ); and plural resin layers ( 11 ). In the LED module ( 10 ), the LEDs ( 12 ) are mounted on a mounting surface of the LED substrate ( 13 ). Each resin layer ( 11 ) is stacked on a surface of each LED ( 12 ) opposite to the LED substrate ( 13 ). Adjacent resin layers ( 11 ) stacked on the LEDs ( 12 ) are separated from each other.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/JP2017/042268, filed Nov. 24, 2017, claiming priority to JapanesePatent Application No. 2017-016036, filed Jan. 31, 2017, the contents ofall of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to an LED module for flashing lamp and aflashing lamp.

BACKGROUND ART

Flashing devices using xenon lamps as light sources are used for guidinga landing aircraft to a runway in an airport or the like (see PatentLiteratures 1 to 4).

CITATION LIST Patent Literature

Patent Literature 1: JP 2006-156287 A

Patent Literature 2: JP 2008-112628 A

Patent Literature 3: JP 2010-182495 A

Patent Literature 4: JP 2010-247576 A

SUMMARY OF INVENTION Technical Problem

If the above-described xenon lamp can be replaced with a light emittingdiode (LED) lamp, it is possible to greatly extend the life of the lampand reduce the power consumption. Hence, the inventors of the presentinvention have intensively researched on a flashing lamp provided withan LED as a light source. However, it has been found that when an LED isused, the LED chip may be damaged due to pulse lighting for a flash.

Hence, it is an object of the present invention to provide an LED modulethat can prevent breakage of an LED chip due to pulse lighting for aflash when the LED module is used in a flashing lamp.

Solution to Problem

In order to achieve the above object, according to one aspect of thepresent invention, is provided an LED module for flashing lamp whichincludes: an LED substrate plural LEDs and plural resin layers. In theLED module, the LEDs are mounted on a mounting surface of the LEDsubstrate. Each resin layer is stacked on a surface of each LED oppositeto the LED substrate. Adjacent resin layers stacked on the LEDs areseparated from each other.

According to another aspect of the present invention, there is provideda flashing lamp which includes: an LED module serving as a light source;a light distribution unit; a housing having an opening; and a lighttransmissive cover. In the flashing lamp. the LED module is the modulefor flashing lamp according to the present invention. The LED module andthe light distribution unit are disposed inside the housing. The lightdistribution unit is disposed on a light emission side of the LEDmodule. The light transmissive cover is disposed over the opening of thehousing.

Advantageous Effects of Invention

According to the LED module of the present invention, even if the LEDmodule is used in a flashing lamp, breakage of a LED chip due to pulselighting for a flash can be prevented.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C are schematic diagrams showing an example of theconfiguration of an LED module of the first example embodiment. FIG. 1Ais a plan view. FIG. 1B is a partial plan view of FIG. 1A. FIG. 1C is across-sectional view taken along the line I-I in FIG. 1B.

FIG. 2 is a cross-sectional view showing an example of the configurationof a flashing lamp of the second example embodiment.

FIG. 3 is a perspective view showing an example of installation of alamp of the first example embodiment.

DESCRIPTION OF EMBODIMENTS

In the LED module for flashing lamp of the present invention, forexample, adjacent LEDs are separated from each other.

In the LED module for flashing lamp of the present invention, forexample, the number of LEDs mounted on the mounting surface of the LEDsubstrate is 4 to 25 per 120 mm².

In the LED module for flashing lamp of the present invention, forexample, a distance between the adjacent LEDs is 0.2 to 0.5 mm.

In the LED module for flashing lamp of the present invention, forexample, an LED has a width of 1.8 to 5.3 mm.

The LED module for flashing lamp of the present invention has, forexample, an effective luminous intensity of 6,000 to 20,000 cd perflashing time of 1 to 5 msec.

The LED module for flashing lamp of the present invention has, forexample, a brightness of 300,000 to 1,600,000 lumen (lm).

The flashing lamp according to the present invention is, for example,for flashing for the landing guidance of an aircraft.

As a result of the intensive research, the inventors of the presentinvention have found that breakage of the LED in the LED module iscaused by expansion and contraction due to pulse lighting for a flash.That is, in production of a common small-area ultra-high luminous fluxLED module, plural LED chips are mounted at high density on an LEDsubstrate, and then a resin layer is uniformly formed on the entireregion where the LED chips are mounted. When the LED module is used as alight source of a flashing lamp, pulse lighting of repeatedly turning onand off every several msec is required, which results in repetition ofrapid thermal expansion and thermal contraction in the LED module. Ithas been found that, in the LED module, since the metal substrate andthe resin layer stacked on the LED chip usually have differentcoefficients of thermal expansion, cracks occur in the resin layer, andthe LED is damaged or broken by the cracks. Hence, the inventors havemade the present invention in which the resin layer does not cover theentire region where the LED chips are mounted but the resin layer isstacked on each of the LEDs. According to the present invention, sincethe resin layer is stacked on each LED, for example, the force ofthermal expansion or thermal contraction generated in a large resinlayer covering the LEDs is not applied to one LED, and since the resinlayer is individually formed on each LED, the force of thermal expansionor thermal contraction generated in each resin layer can also bereduced. Therefore, according to the LED module of the presentinvention, for example, even when the LED module is used as a lightsource of a flashing lamp that requires pulse lighting, theabove-described breakage of the LED can be prevented as well aslong-term reliability can be secured.

Descriptions will be made as regards the lamp of the present inventionbelow more in detail with reference to the drawings. The presentinvention, however, is not limited to the following description. In thefollowing FIGS. 1 to 3, identical parts are indicated with identicalreference signs.

First Example Embodiment

The present example embodiment shows an example of an LED module forflashing lamp of the present invention. The LED module for flashing lampof the present example embodiment is for a flashing lamp used in aflashing device for landing guidance of an aircraft, for example, but isnot limited thereto. An example of the configuration of the LED moduleof the present example embodiment is shown in FIG. 1.

FIG. 1A is a plan view of an LED module 10, FIG. 1B is a partial planview showing a region surrounded by the dotted line at the upper left inFIG. 1A, and FIG. 1C is a cross-sectional view taken along the line I-Iin FIG. 1B. The LED module 10 includes an LED substrate 13, plural LEDs12, and resin layers 11. The LEDs 12 are mounted on a mounting surfaceof the LED substrate 13, each resin layer 11 is stacked on the surfaceof each LED 12 opposite to the LED substrate 13, and adjacent resinlayers 11 stacked on the LEDs 12 are separated from each other.

The LED module 10 serves as a light source in a flashing lamp. The typeof the flashing lamp is not particularly limited, and may be, forexample, a flashing lamp for landing guidance of an aircraft. Asdescribed above, a xenon lamp is generally used as the light source ofthe flashing lamp, and the module for flashing lamp of the presentinvention can be used as a substitute for the xenon lamp, for example.The luminous intensity of the LED module 10 can be appropriatelydetermined, for example, depending on the application. As being thesubstitute for the xenon lamp, for example, the module preferably hasthe optical characteristics (e.g., luminous intensity, effectiveluminous intensity per predetermined flashing time, etc.) comparable toor higher than those of the xenon lamp. The optical characteristics ofthe LED module 10 can be appropriately set depending on, for example,the size of the LED module 10, the number of LEDs 12 per unit area, andthe like.

The LED substrate 13 is not particularly limited, and may be, forexample, an insulating substrate. Examples of the insulating substrateinclude a metal substrate made of aluminum, copper, or the like; and aresin substrate made of paper phenol, paper epoxy, glass composite, orthe like. The size of the LED substrate 13 is not particularly limited,and can be appropriately determined depending on, for example, the sizeof the flashing lamp containing the LED module 10, the use location orthe application of the flashing lamp, or the like. In the flashing lampfor landing guidance, the area of the region in the mounting surfacewhere the LEDs 12 are mounted is, for example, 60 to 120 cm².

The LEDs 12 are stacked on the mounting surface of the LED substrate 13,and each resin layer 11 is stacked on the surface of each LED 12opposite to the mounting surface of the LED substrate 13. In the LEDmodule 10 of the present invention, it is only required that theadjacent resin layers 11 on the LEDs 12 are separated from each other.The adjacent LEDs 12 may be separated from each other as shown in FIG.1, for example, whereas the present invention is not limited thereto,and the adjacent LEDs 12 may be in contact with each other.

The conditions for mounting the LEDs 12 on the LED substrate 13 are notparticularly limited as described above, and can be appropriately setdepending on the intended optical characteristics. The number of LEDs 12mounted on the mounting surface of the LED substrate 13 is, for example,4 to 25 per 120 mm². The total number of LEDs 12 mounted on the LEDsubstrate 13 is, for example, 200 to 2,000.

The shape of the LED 12 is not particularly limited, and is generally asquare shape or a rectangular shape. The size of the LED 12 is notparticularly limited, and in the case of the square, the length of theside (arrow Y in FIG. 1) is, for example, 1.8 to 2.2 mm, 3 to 3.5 mm, or4 to 5.3 mm, and in the case of the rectangle, the length of the shortside is, for example, the same as the length of the square, and theratio of the short side to the long side is, for example, 1:1 to 1:3. Inthe mounting surface of the LED substrate 13, when the adjacent LEDs 12are separated from each other, the width between the adjacent LEDs 12is, for example, 0.2 to 0.5 mm.

The resin layer 11 is stacked on the surface of the LED 12 as describedabove. The resin layer 11 is, for example, a phosphor resin layercontaining a phosphor and a resin, and the color of light of the LEDmodule 10 can be set by the phosphor. In the present invention, the typeand the like of the phosphor are not limited by any means, andconventionally known phosphors can be used. Examples of the phosphorinclude Y₃Al₅O₁₂:Ce and Tb₃Al₅O₁₂:Ce.

The resin layer 11 can be formed, for example, by supplying a resin tothe surface of the LED 12 and solidifying the resin. When the resinlayer 11 is the phosphor resin layer, for example, the resin layer 11can be formed by supplying a mixture of the phosphor and the resin tothe surface of the LED 12 and solidifying the mixture. The type of theresin is not particularly limited, and examples thereof include an epoxyresin and a silicone resin. The ratio of the phosphor to the resin isnot particularly limited, and, for example, the phosphor is 50 to 80parts by weight with respect to 100 parts by weight of the resin. Themixture may include, for example, other additives in addition to theresin and the phosphor, and examples of the additive include silica andalumina.

A method of supplying the mixture to the surface of the LED 12 is notparticularly limited, and the mixture may be applied or sprayed. Sincethe adjacent resin layers 11 need to be separated from each other asdescribed above, the resin layers 11 may be formed by supplying themixture to the surfaces of the exposed LEDs 12 by using, for example, apattern mask covering the space between the LED 12 and the LED 12 sothat the adjacent resin layers 11 are separated from each other. Themethod of solidification is not particularly limited, and may be, forexample, a drying treatment or the like.

A width (arrow X in FIG. 1B) between the adjacent resin layers 11 is notparticularly limited, and is, for example, 0.2 to 0.5 mm. A thickness ofthe resin layer 11 is not particularly limited, and is, for example, 100to 300 μm.

The resin layer 11 may be formed on the entire surface of the LED 12 ora part of the surface of the LED 12. In the latter case, the resin layer11 is preferably stacked on, for example, the region of 90% or more ofthe surface of one LED 12.

Since the LED module 10 of the present invention can be a substitute fora xenon lamp in a flashing lamp as described above, the opticalcharacteristics thereof are preferably set as follows, for example. TheLED module 10 has a luminous intensity (cd) of, for example, 6,000 to20,000 or 60,000 to 200,000. In the present invention, the luminousintensity means an effective luminous intensity. The unit of the lightoutput of the flashing lamp is the effective luminous intensity (cd).The effective luminous intensity of the LED module 10 is, for example,6,000 to 20,000 cd per flashing time of 1 to 5 msec. In the presentinvention, the effective luminous intensity (cd) per unit of flashingtime is expressed by the value calculated by the relational expression(Blondel-Rey-Douglas equation) between the light emission luminousintensity (luminous intensity (cd) at the moment of flashing) and thelight emission time. The effective luminous intensity (Ie) can beexpressed by, for example, the following equation.

$\begin{matrix}{{{Ie} = \frac{\int_{t_{1}}^{t_{2}}{{I(t)}{dt}}}{a + \left( {t_{2} - t_{1}} \right)}}{a = 0.21}} & {{Equation}\mspace{14mu} 1}\end{matrix}$t1, t2: value at which Ie shows maximum value during flashing timeI(t): luminous intensity at time t

Second Example Embodiment

The present example embodiment shows an example of a flashing lamp ofthe present invention. The flashing lamp of the present exampleembodiment includes the LED module of the present invention, and is usedin a flashing device for landing guidance of an aircraft, for example,but is not limited thereto. An example of the configuration of theflashing lamp of the present example embodiment is shown in FIG. 2.

FIG. 2 is a cross-sectional view showing an example of the flashing lampof the present example embodiment. A flashing lamp 20 includes an LEDmodule 10 as a light source, a light distribution unit 21, a housing 22having an opening, and a light transmissive cover 23. The LED module 10is the LED module 10 of the first example embodiment. The LED module 10and the light distribution unit 21 are disposed inside the housing 22,and the light transmissive cover 23 is disposed over the opening of thehousing 22. Regarding the LED module 10, the reference can be made tothe description of the first example embodiment.

The light distribution unit 21 is disposed on the light emission side ofthe LED module 10. That is, in FIG. 2, the light distribution unit 21 isdisposed in the direction in which the LED module 10 emits light (on theleft side relative to the LED module 10). The light distribution unit 21is a unit configured to transmit the light emitted by the LED module 10to the light transmissive cover 23 side by, for example, reflection,condensation, diffusion, or the like. The type of the light distributionunit 21 is not particularly limited, and examples thereof include areflector and a lens. The light distribution unit 21 may be, forexample, one of the reflector and the lens, or a combination of thereflector and the lens.

When the light distribution unit 21 is a reflector, the material forforming the reflector is not particularly limited, and examples thereofinclude metals such as aluminum, magnesium, and alloys thereof, and thelike; and resins such as PC (polycarbonate), PBT (polybutyleneterephthalate), and the like. As the reflector, for example, a reflectorwhose reflection efficiency is further improved by applying highreflection processing on the reflection surface may be used. The highreflection processing is, for example, plating, application of a highreflection paint, or the like.

When the light distribution unit 21 is a reflector, the shape of thereflector is not particularly limited. The reflector has, for example, acylindrical shape as shown in FIG. 2. It is preferable that theLED-mounting region in the mounting surface of the LED module 10 islocated at one of openings of the cylindrical reflector (on the rightside in FIG. 2) and the light from the LED module 10 is emitted to theinside of the cylindrical reflector. For example, as shown in FIG. 2,the cylindrical reflector may have a tapered shape whose inner wallwidens as it extends from the LED module 10 toward the opening of thehousing 22, and this shape may be referred to as an umbrella shape, forexample. The cross section of the inner wall of the cylindricalreflector extending from the LED module 10 toward the opening of thehousing 22 may have, for example, an arc shape as shown in FIG. 2, ormay have a flat straight shape.

The light distribution unit 21 may be, for example, a lens as describedabove. The lens is disposed on the mounting surface side of the LDEmodule 10, for example, so as to receive light emitted from the LEDmodule 10 and to distribute the light by diffusion, scattering, or thelike. The lens may be, for example, a convex lens having a sphericalsurface on the side of the opening of the housing 22.

The material for forming the housing 22 is not particularly limited andexamples thereof include aluminum and resins. The shape of the housing22 is not particularly limited, and may be, for example, an umbrellashape as shown in FIG. 2.

The light transmissive cover 23 is disposed so as to cover the openingof the housing 22, and light from the inside of the housing 22 transmitsthe light transmissive cover 23. The material for forming the lighttransmissive cover 23 is not particularly limited as long as most of thelight emitted from the LED module 10 can transmits therethrough, and aspecific example thereof is glass or the like.

As described above, the optical characteristic of the flashing lamp ofthe present invention can be set as desired depending on the number ofmounted LEDs per unit area, the total number of LEDs, the size of theLED substrate, and the like in the LED module. Thus, the flashing lampof the present invention can be configured, for example, so as to haveoptical characteristics comparable to or better than existing xenonlamps, e.g., the required effective luminous intensity per desiredflashing time. For this reason, for example, the flashing lamp of thepresent invention can be totally replaced with xenon lamps, partiallyreplaced with xenon lamps, or sequentially replaced with xenon lamps inan existing sequenced flashing light.

An installation example of the flashing lamp 20 of the present exampleembodiment is described below with reference to FIG. 3. In addition tothe configuration of FIG. 2, for example, the lamp 20 of the presentexample embodiment may further include an arm 33 and a leg 34 and may beinstalled on the ground by the leg 34. The flashing lamp 20 of thepresent example embodiment may further include, for example, a cable 32for supplying power to the LED module 10. Furthermore, the flashing lamp20 of the present example embodiment may be installed on a pole providedon the ground, for example, and the number thereof is not particularlylimited.

The flashing lamp 20 of the present example embodiment is configured toachieve flashing 120 times per minute, for example. For example, whenthe flashing lamp 20 is provided in a large airport having a pluralityof runways, 8 to 29 flashing lamps 20 are arranged at intervals of about30 m from the approach direction of the aircraft toward the end of therunway. Furthermore, for example, when the flashing lamp 20 is providedin a small airport where the number of arrival and departure of anaircraft is small and is provided with only one short runway, oneflashing lamp 20 is arranged at each side of the runway end in the shortdirection so as to flash (blink) a total of two lamps simultaneously.Furthermore, when the flashing lamp 20 is installed in an airport wherean aircraft cannot enter the runway straight, for example, the flashinglamp 20 is strategically arranged at a predetermined position on theapproach to the runway, for example, every several kilometers. Theflashing lamp 20 is configured such that the brightness can be switchedto three levels in accordance with, for example, the standardspecification of the Ministry of Land, Infrastructure, Transport andTourism. Among these three levels of brightness, “High”, which is thebrightest level, is used, for example, in the daytime of poor visibilitydue to fog, rain, or the like, “Low”, which is the darkest level, isused, for example, in the night, and “Middle”, which is the intermediatelevel, is used, for example, in the evening.

While the present invention has been described above with reference toillustrative example embodiments, the present invention is by no meanslimited thereto. Various changes and variations that may become apparentto those skilled in the art may be made in the configuration andspecifics of the present invention without departing from the scope ofthe present invention.

INDUSTRIAL APPLICABILITY

According to the present invention, even if the LED module is used in aflashing lamp, breakage of a LED chip due to pulse lighting for a flashcan be prevented.

REFERENCE SIGNS LIST

-   10 LED module-   11 resin layer-   12 LED-   13 LED substrate-   20 flashing lamp-   21 light distribution unit-   22 housing-   23 light transmissive cover

The invention claimed is:
 1. An LED module for a flashing lampcomprising: an LED substrate; plural LEDs; and plural resin layers,wherein the LEDs are mounted on a mounting surface of the LED substrate,each resin layer is stacked on a surface of each LED opposite to the LEDsubstrate, adjacent resin layers stacked on the LEDs are separated fromeach other, adjacent LEDs are separated from each other; and the numberof LEDs mounted on the mounting surface of the LED substrate is 4 to 25per 120 mm ².
 2. The LED module for flashing lamp according to claim 1,wherein a distance between the adjacent LEDs is 0.2 to 0.5 mm.
 3. Themodule for flashing lamp according to claim 1, wherein the LED has awidth of 1.8 to 5.3 mm.
 4. The LED module for flashing lamp according toclaim 1, wherein an effective luminous intensity is 6,000 to 20,000 cdper flashing time of 1 to 5 msec.
 5. The LED module for flashing lampaccording to claim 1, wherein a brightness is 300,000 to 1,600,000 lumen(lm).
 6. The LED module for flashing lamp according to claim 1, whereinthe resin layer is a phosphor resin layer.
 7. A flashing lampcomprising: an LED module serving as a light source; a lightdistribution unit; a housing having an opening; and a light transmissivecover, wherein the LED module is the module for flashing lamp accordingto claim 1, the LED module and the light distribution unit are disposedinside the housing, the light distribution unit is disposed on a lightemission side of the LED module, and the light transmissive cover isdisposed over the opening of the housing.
 8. The flashing lamp accordingto claim 7, wherein the flashing lamp is for flashing for the landingguidance of an aircraft.